5 or 6 speed 'box ?

[FossilFuelled]

I was told once that the gearboxes fitted onrecent-ish Caterham were quite different, allegedly for different use. I was told that the first ratios in the 6 speed ones were very close and that the 6th ratio was equivalent to 4th on the 5 speed gearbox. Is that true? Does this mean that the 5 speed gearbox equipped cars are more suited to "relaxed" cruising and long distance driving. Also, is a 6 speed gearbox unbearable on long distances?

Thanks

[Tango7]

6th is a direct 1:1 which is equivalent to 4th on a 5 speed box.

Which engine are you thinking of with the gearbox? If its a K series, the 6 speed box suits it fine. VX, Xflows and, I expect, Zetecs suits the 5 speed box better. For touring purposes the final drive (diff ratio) will play the biggest factor with most 6 speeds usually mated with a 3.62 final drive and 5 speeds mated to a 3.91 final drive.

Sprinters typically move the 3.62 to a 3.91 with a 6 speed box which gives them a decent increase on acceleration but does mean it will run out of steam around 120. For a 5 speed box, the upgrade is to the rare 4.1 final drive to achieve a similar increase in acceleration/loss of top end.

So, it depends on what you want from your car and your budget. A 1600k series engine with a 5 speed box is excellent for touring and general road use but does have a significant drop in revs between changes which can be a problem for trackdays and sprinting. A 1600/1800k series engine with a 6 speed box and 3.62 final drive is an excellent combination and whilst the revs at 70-75 mph will be about 4k, this is reasonably comfortable still and generally acceptable to all owners. The 6 speed does carry a premium when you buy the car (possibly a grand more) but its a desirable option and gets its money back when you move on to another car.

T

[ham]

If its any help Iv'e got a five speed box on my new Sigma 125 and I find it great for road use, don't know about track.

[CanAm]

I have a 6-speed 1600 Supersport with the 3.91 final drive, so it's great on acceleration, but a little buzzy on the motorway; as you will have seen this is exactly the same as a normal 5-speed cruising in fourth.
But as most of us wear earplugs anyway, you don't really notice the noise; and on a 350 mile (mostly autoroute) trip to the Loire Valley I got almost exactly the same fuel consumption as my mate's 5-speed Roadsport (though he has a bit more DVA power than me).
It's great for 0-60 times as, unlike the 5-speed, there is no big rev-drop when changing into second (which is good for 64mph).
I did toy with the idea of changing to the 3.62 final drive for slightly more relaxed cruising, but as I hardly ever use M-ways I decided to stick with the lower ratio.

Edited by CanAm on Monday 5th November 12:50

[lord summerisle]

the other option which some have is get BGH (i think it is) to modify the 5 speed box to alter the 1st ratio (which i believe was origonally designed for Sierra's and towing caravans) so there isnt the same drop 1st>2nd and sometimes alter 5th as well for cruising, depending on your needs

[MGYoung]

I have a 1400SS (approx. 120-ish bhp) with the 6 speed box and a 3.62 diff. I find its a good combination for road use as the 1400SS needs revs if you are looking for decent acceleration in 1st, 2nd and 3rd gears. 70mph equals around 4000rpm.

[Murph7355]

FossilFuelled said:

...Also, is a 6 speed gearbox unbearable on long distances?

Thanks

No - no matter what anyone may try and tell you, on a motorway the last thing you're that bothered about are a few extra revs. Wind and general road noise are far worse.

A 7 isn;t well suited to motorway cruising. But it can do it easily enough and a 6spd is equally fine.

On the upside, the 6spd allows peaky engines to perform very well, the shift quality's great and the box is pretty light.

[CanAm]

Like Murph said, the shift action is brilliant, the ratios are well chosen to match the K-Series and with all the wind noise around your ears you'll never notice a few extra revs, and that's with the low final drive.
The experience of zipping through the gears in quick succession is not to be missed. If you use full revs on a Supersport it only drops to around 5500 on the upshift .

[casbar]

Did 2000 miles in France a couple of years ago, with a R300 and a 6 speed box, don't remember it being an issue. But once on the track the 6 speed is ideal

[sjmmarsh]

You are driving a sports car - not a motorway cruiser - so get the 6 speed box. It is miles better and the engine will never be that far away from being 'on cam', which helps the acceleration....

Steve